The ability to monitor and measure protein kinase activity in tumorigenesis and cancer can be indicative of and critical to the transformation process and therefore represents an attractive diagnostic strategy, with a multi-billion dollar market opportunity. In this proposal, we aim to develop a novel, high affinity fluorescent nanosensor and homogeneous assay system for monitoring the phosphorylation of a bona fide peptide substrate by c-Abl, an important kinase involved in the etiology of chronic myelogenous leukemia (CML), using FRET. The technology deployed during this phase of the proposal will directly translate into the development of a sensitive platform for the diagnosis of CML. In specific aim 1, we will synthesize the high-affinity nanosensor. In specific aim 2, we will develop a sensitive 1-step assay using this reagent. Specific aim 3 will elaborate on this and test the effectiveness of the nanosensor in measuring c-Abl activity in CML-positive cell lysates. Given the fact that ~400 disorders such as cancer have been associated with protein kinases, the development of a family of sensitive nanosensors such as the 1 proposed in this grant application will facilitate the diagnosis of these diseases sensitively and selectively and therefore becomes of paramount importance and will find immense utility in all the various facets of our healthcare, from drug-discovery to patient health and point-of-care diagnostics. [unreadable] [unreadable] [unreadable]